GB2248486A - Venting valve - Google Patents

Abstract

A valve especially for use in venting entrapped air from a waterproof survival suit (5) has a housing (2) providing a valve seat with a diaphragm (1) normally seated on the housing but movable away from it to permit one way flow of air, the housing carrying a spring (7) normally held off the diaphragm by a soluble tablet (9) but movable to hold the diaphragm against the valve seat when the tablet dissolves on immersion in water. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO VALVES This invention relates to diaphragm or other valves and particularly but not exclusively to valves for use in the venting of air from survival or other dry or waterproof suits.

It is known for air to be vented from such suits or clothing by means of diaphragm valves fitted into typically the shoulders and knees or ankles of the suit in such a manner that air under low pressure may escape from the suit due, in part, to the pressure of surrounding water when the suit and possibly the wearer are partly or wholly immersed in water or other fluid.

A purpose of such venting is to reduce the buoyancy of the suit so that the wearer may more easily reach an exit from a submerged vehicle such as an aircraft especially when the exit may be below him.

It is thus important that the air be vented as rapidly as possible from the suit and that as little water as possible should enter the suit.

It is known for diaphragm valves to be used for such purposes. These valves are able to vent a large amount of air rapidly they use relatively large diameter diaphragms made of relatively soft rubber or other material, seating onto a flat or knife edged ring of harder material.

In present valves, while the air is flowing out rapidly, which may be at the start of the venting operation, there is little opportunity for water to enter from outside the valve, due to the rapid flow of air from the inside to the outside water. However it has been found that, as the flow of air outwardly decreases or ceases, the movement of the wearer or the lapping movement or wase action of the water may cause the diaphragm to open and close with relatively little or no passage of air.In such circumstances a greater or leaser quantity of water ma enter the valve, particularly when a leg movement is describing a radial path through the water as this may cause a partial suction or venturi effect on the water side of the valve diaphragm, and may cause a soft diaphragm of relatively large diameter to lift, possible in a fluttering motion, and thus admit water.

Thus the said large and soft diaphragm may be useful in order rapidly to vent air but has disadvantages in respect of the entry of water, due to the ease of opening or lifting said diaphragm valve from its seating.

It is an object of the present invention to obviate or mitigate these disadvantages.

According to the present invention there is provided a valve comprising a valve housing defining a valve seat, a diaphragm or plate seating on said seat and moveable away from said seat to permit fluid to flow through the valve in one direction and returnable against said seat to prevent fluid flow in the reverse direction, a resilient member carried by said housing and biased towards said diaphragm, means for retaining said resilient member in said biased condition and for releasing said resilient member such that it forces said diaphragm against said valve seat when said retaining means are removed.

Preferably said retaining means comprises a water soluble tablet, capsule or block.

Preferably said resilient member comprises a helically coiled spring fixed at one end oto said valve housing and mounted on the downstream side of said diaphragm or plate the other, free end of the spring extending through the coils thereof and trapping said retaining means between itself and the housing.

Preferably the housing comprises a first body member including said valve seat and said diaphragm or plate and a cap threadably mounted on said body member, said cap carrying said resilient means and being provided with vent passages therethrough.

Preferably a cover is provided on said cap to shield said retaining means. A slot may be provided in said cover, which may be transparent, to allow ingress of water or other fluid to the retaining means. Alternative apertures may be provided at circumerentially spaced intervals around the periphery of the cover and baffle means may be provided on the cap to shield said retaining means from said aperture.

Preferably the valve housing has a threaded outer portion for carrying a nut by which the valve can be mounted on a planar member. Preferably the planar member is the fabric of an immersion or survival suit.

Thus while the tablet remains dry and hard, the spring is retained in the non effective mode. The tablet will remain dry in the presence of rain, but will be flooded on immersion of the system.

Advantageously the system may be visually checked before use, as on aircraft transit, and in the event of immersion permit the venting of air before the tablet softens and the spring mechanism prevents the later entry of water into the suit. Rapid action will retain air if desirable.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, of which, Fig. 1 is a schematic drawing of a diaphragm valve; Fig. 2 is a section "A-A" on Fig. 1, and the valve shown in the drawings is for the venting of air or other fluid from typically, a waterproof or dry or survival suit, having one or more such valves fitted to the suit.

Fig. 3 is a schematic drawing of a modified valve.

The diaphragm (or plate) valve 1 is fitted to a cylindrical valve housing 2, and peTmits air or fluid to pass from the suit 5 outwardly to vents 8 in a cap 3 fitted on the housing. A coiled and compressed spring 7 is held in place, and is located with its axis co-incident with the valve housing axis by a loop of spring wire which extends from the lower end of the spring 7, and passes through the centre of the spring and a slot in the valve housing cap 3. A soluble tablet 9, is fitted under this loop of spring wire so as to prevent its return towards the diaphragm 1 unless the tablet has softened or dissolved. If this occurs the spring will expand downwardly so as to press annularly onto the diaphragm 1 to force it against its annular seat defined by a step 21 in the housing 2.Advantageously this may occur a suitable time after the immersion of the valve system, and thus after the air has been vented, whether the wearer of the suit is conscious or not.

The system may thus be used to vent air from a suit, and then increase the return pressure on the diaphragm so as to prevent diaphragm flutter and ingress of water, or with suitable adjustments to the dissolving time of the capsule or tablet, and the tension of the spring, the same system may be used to cause the virtually immediate closure of the valve on immersion, which may be desirable for a wearer falling overboard and who may also be unconscious.

An outer or top cover 6 of the valve screwed in a watertight manner onto the top of the housing cap 3, to protect the tablet from damage and rain, permits water to reach both sides of the tablet when the system is immersed and water enters the top cover 6 through a slot 10 in the housing cap 3. A small hole may be provided in this top cover to let air in it get out and prevent airlock inside the top cover.

A body locking nut 4, screws up on a threaded part of the valve housing 3, so as to tighten and seal onto the fabric of the suit 5 which is sandwiched between the flange 24 of the nut and the step 21 of the housing.

Fig. 3 shows a modified valve wherein water is permitted to enter the top cover 6 through the additional vents 11, and wherein rain etc. is prevented from reaching the tablet 9, by baffle means in the form of the annuluar inclined frusto conical ring 12, but will however permit the flooding upon immersion.

In both the valves described above the top cover is securely fitted to the valve housing cap, possibly by means of screw threads as illustrated. The valve housing and its cap may be screwed together as illustrated and the cap is easily removable together with the top cover, the tablet and the spring, as a unit, leaving the diaphragm valve intact so that the suit may be cleaned when turned inside out.

In both arrangements the system may be visually checked by the wearer for tablet deterioration since the top cover can be of robust but transparent material, which is so shaped as to offer the minimum obstruction to the wearer when working.

As described previously the same system may be used with suitably adjusted spring tensions and tablet dissolve times, so as to produce an almost immediate valve closure upon immersion of the suit and wearer as in a man overboard situation, and wherein flotation is desirable as well as heat insultation from the trapped air which is prevented from venting, after immersion.

Various modifications can be made without departing from the scope of the invention. The housing may be attached to the suit by a bolted plate or by welding, adhesive or the like. The diaphragm may seat onto the housing either onto a flat surface in the housing as illustrated or onto a circular knife edge in such manner that fluid such air may easily pass outwardly as the diaphragm lifts off its seat to permit such air to pass, but when the air or other fluid passage slows or stops it will return to its seating, due to its elastomeric material of which the diaphragm may be made or if the diaphragm is more solid and therefore stiffer in form the diaphragm may be in the form of a plate which is returned to its seat by a soft spring. The tablet may be replaced by a capsule or block. The tablet, capsule or block is preferably white so that it can be readily visually checked.

Claims (10)

Claims

1. A valve comprising a valve housing defining a valve seat, a diaphragm or plate seating on said seat and moveable away from said seat to permit fluid to flow through the valve in one direction and returnable against said seat to prevent fluid flow in the reverse direction, a resilient member carried by said housing and biased towards said diaphragm, means for retaining said resilient member in said biased condition and for releasing said resilient member such that it forces said diaphragm against said valve seat when said retaining means are removed.

2. A valve according to claim 1 wherein said retaining means comprises a water soluble tablet, capsule or block.

3. A valve according to claim 1 or claim 2 wherein said resilient member comprises a helically coiled spring fixed at one end onto said valve housing and mounted on the downstream side of said diaphragm or plate the other, free end of the spring extending through the coils thereof and trapping said retaining means between itself and the housing.

4. A valve according to any of the preceding claims wherein the housing comprises a first body member including said valve seat and said diaphragm or plate and a cap threadably mounted on said body member, said cap carrying said resilient member and being provided with vent passages therethrough.

5. A valve according to claim 4 wherein a cover is provided on said cap to shield said retaining means.

6. A valve according to claim 5 wherein a slot is provided in said cover to allow ingress of water or other fluids to the retaining means.

7. A valve according to claim 5 wherein apertures are provided at circumerentially spaced intervals around the periphery of the cover and baffle means are provided on the cap to shield said retaining means from said apertures.

8. A valve according to any of the preceding claims wherein the valve housing has a threaded outer portion for carrying a nut by which the valve can be mounted on a planar member.

9. A valve substantially as hereinbefore described with reference to the accompanying drawings.

10. Any novel subject matter or combination including novel subject matter disclosed in the foregoing specification or claims and/or shown in the drawings, whether or not within the scope of or relating to the same invention as any of the preceding claims.